In recent years, progress has been made in developing electrically assisted bicycles having an electric motor mounted on the body of the bicycle which can be driven by human power and adapted to assist in the human drive force.
With reference to FIG. 49 schematically showing the construction of a bicycle equipped with an electric motor 2, the torque generated by stepping on pedals on the body 1 of the bicycle is detected by a torque sensor 21, which in turn feeds a detection signal to a controller 22. In response to the torque detection signal input, the controller 22 prepares a torque command in accordance with the signal, giving the command to the motor 2. Consequently, the bicycle body 1, which is given human torque, is further supplied with torque delivered by the motor according to the input torque value to supplement the human drive force.
The bicycle body 1 has mounted thereon a battery 20 serving as the power supply for the motor 2. When the output voltage of the battery 20 has dropped, the battery 20 is removed from the bicycle body 1 and charged by a device specifically designed for the bicycle.
However, the above charging method requires the procedure of connecting the output terminals of the charging device to the charging terminals of the battery 20 by a cable, hence the problem that this procedure is cumbersome.
Accordingly an object of the present invention is to provide a charging system adapted to charge the battery without necessitating a procedure for connecting the system to the battery with a cable.